Thanks everyone for the comments, lots of helpful suggestions. For those of you who actually have any of the quieter exhausts, can you tell me which DP you chose and if you had any issues with fitment. I am just really OCD about stuff like this and I would be a lot more comfortable choosing a combination that has been verified by a few people. Also, if you needed adapters or other extras and you could list them that would be awesome.

Newb here, just traded my Boxster S for an '06 WRX wagon last week and I couldn't be happier. I'm looking at a TBE but want it as quiet as possible. How does the SPT cat back compare sound and flow wise to the Whisper or Hush?